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-rw-r--r--arch/x86/kvm/emulate.c51
-rw-r--r--arch/x86/kvm/x86.c23
2 files changed, 74 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index f1e3be18a08f..f5302da9af21 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1877,6 +1877,51 @@ setup_syscalls_segments(struct x86_emulate_ctxt *ctxt,
ss->p = 1;
}
+static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt)
+{
+ struct x86_emulate_ops *ops = ctxt->ops;
+ u32 eax, ebx, ecx, edx;
+
+ /*
+ * syscall should always be enabled in longmode - so only become
+ * vendor specific (cpuid) if other modes are active...
+ */
+ if (ctxt->mode == X86EMUL_MODE_PROT64)
+ return true;
+
+ eax = 0x00000000;
+ ecx = 0x00000000;
+ if (ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx)) {
+ /*
+ * Intel ("GenuineIntel")
+ * remark: Intel CPUs only support "syscall" in 64bit
+ * longmode. Also an 64bit guest with a
+ * 32bit compat-app running will #UD !! While this
+ * behaviour can be fixed (by emulating) into AMD
+ * response - CPUs of AMD can't behave like Intel.
+ */
+ if (ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
+ ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
+ edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx)
+ return false;
+
+ /* AMD ("AuthenticAMD") */
+ if (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
+ ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
+ edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx)
+ return true;
+
+ /* AMD ("AMDisbetter!") */
+ if (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
+ ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&
+ edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx)
+ return true;
+ }
+
+ /* default: (not Intel, not AMD), apply Intel's stricter rules... */
+ return false;
+}
+
static int em_syscall(struct x86_emulate_ctxt *ctxt)
{
struct x86_emulate_ops *ops = ctxt->ops;
@@ -1890,9 +1935,15 @@ static int em_syscall(struct x86_emulate_ctxt *ctxt)
ctxt->mode == X86EMUL_MODE_VM86)
return emulate_ud(ctxt);
+ if (!(em_syscall_is_enabled(ctxt)))
+ return emulate_ud(ctxt);
+
ops->get_msr(ctxt, MSR_EFER, &efer);
setup_syscalls_segments(ctxt, &cs, &ss);
+ if (!(efer & EFER_SCE))
+ return emulate_ud(ctxt);
+
ops->get_msr(ctxt, MSR_STAR, &msr_data);
msr_data >>= 32;
cs_sel = (u16)(msr_data & 0xfffc);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9aac6d69bffa..66d2844fd705 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4655,6 +4655,28 @@ static int emulator_intercept(struct x86_emulate_ctxt *ctxt,
return kvm_x86_ops->check_intercept(emul_to_vcpu(ctxt), info, stage);
}
+static bool emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,
+ u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
+{
+ struct kvm_cpuid_entry2 *cpuid = NULL;
+
+ if (eax && ecx)
+ cpuid = kvm_find_cpuid_entry(emul_to_vcpu(ctxt),
+ *eax, *ecx);
+
+ if (cpuid) {
+ *eax = cpuid->eax;
+ *ecx = cpuid->ecx;
+ if (ebx)
+ *ebx = cpuid->ebx;
+ if (edx)
+ *edx = cpuid->edx;
+ return true;
+ }
+
+ return false;
+}
+
static struct x86_emulate_ops emulate_ops = {
.read_std = kvm_read_guest_virt_system,
.write_std = kvm_write_guest_virt_system,
@@ -4685,6 +4707,7 @@ static struct x86_emulate_ops emulate_ops = {
.get_fpu = emulator_get_fpu,
.put_fpu = emulator_put_fpu,
.intercept = emulator_intercept,
+ .get_cpuid = emulator_get_cpuid,
};
static void cache_all_regs(struct kvm_vcpu *vcpu)